In the past, since it was seldom that general network service users at home keep their machine connecting to a public network all the time, they were little conscious of network security.
Conventionally, corporate network security management has been performed, using firewalls or the like.
It is substantially impossible for general home users to provide their machine or system with a firewall and carry out firewall operation and maintenance for which a lot of technical expertise is required
If general household computers and equipment keep connecting to a public network all the time without being protected by a firewall, it is easy for a third party to intrude into the intra-home network. Consequently, there is a possibility that secret information such as a password, credit ID and ID for electronic commerce (EC) be stolen.
Even when general household computers and equipment keep connecting to a public network all the time via a router, filtering can be performed, but personal authentication or the like must be performed separately. Because building an authentication system requires technical expertise, it is substantially impossible for general home users to use authentication management.
When a cellular mobile device operating outdoors is accessing a network device installed in a home, the absence of an authentication system is a bottleneck of security, so that it will be impossible to remotely operate a crime prevention and security system and download data from a server in the home.
Telephonic communication via networks using Voice over IP (VoIP) or the like is normally arranged such that a subscriber calls another subscriber connecting to a connection server except intra-corporate use thereof. The subscriber, however, cannot call another subscriber that is not connecting to the connection server, which is different from general telephony systems in which calling another subscriber by dialing its telephone number makes the connection thereto.
At the present, when connecting computers and equipment to a public network such as the Internet all the time, a connection device such as a router is used for filtering and connection control or a firewall is installed on a large scale. In this case, because individual devices in a network are concealed, receiving push-type information distribution is generally difficult, requiring knowledge of networking.